The Influence of Ni and V on the Corrosion Resistance of Hot-dipped Galvanizing Coating

The hot-dipped Zn-0.05%Ni and Zn-0.05%Ni-0.05%V coatings were gained by adding a small amount of Ni and V in the zinc bath in order to improve the corrosion resistance of coating.The effects of Ni and V on corrosion resistance were studied by electrochemical impedance spectroscopy,electrochemical polarization and neutral salt spray(NSS) tests.The results show that,compared with pure Zn coating,Zn-0.05%Ni and the Zn-0.05%Ni-0.05%V coatings in 5% NaCl solution are of larger electrochemical impedance,lower corrosion current,larger polarization resistance,less spontaneous corrosion tendency and better corrosion resistance.Zn-0.05%Ni-0.05%V coating shows the best corrosion resistance.To some extent,adding a small amount of Ni and V in the zinc bath suppresses the anodic and cathodic processes of the corrosion of coatings,delays the formation of white rust,enhances the corrosion resistance of coatings.